Fuel systems for engines, e.g., diesel or gasoline engines, may include capless fuel port on a fuel filler pipe coupled to a fuel tank for replenishing fuel in the tank. Such a capless fueling port may include a fuel valve or sealing door which remains closed to seal off fuel system and reduce fuel vapor emissions from the fuel tank to the external atmosphere. The fuel valve or sealing door on the capless fuel port may be opened by inserting a fuel nozzle into the fuel port during refueling. Furthermore, the capless fueling port may be designed to collect and drain residual fuel and contaminants left in the fuel port after the fuel nozzle is removed at the end of refueling.
An example capless fueling port is presented by Gabbey et al in U.S. Pat. No. 6,994,130. Therein, a capless fueling system with a funnel port to receive a fueling nozzle is disclosed. The system has a spring loaded valve that is movable between an open position when the funnel port is open, and a closed position when the fuel valve overlies and seals the funnel port. Further, the system has a motor actuated shield that is adjustable to allow insertion of the fueling nozzle during refueling. The shield may be further adjusted to close the spring loaded valve upon completing refueling. Alternatively, an adjustable latch system which opens the spring loaded valve when a fueling nozzle is inserted in the funnel port during refueling may be employed. The latch system may be further adjusted to allow the valve to close after refueling.
Another example capless fueling system is presented by Aitken in U.S. Pat. No. 7,926,522. Therein, the capless fuel system includes a fuel filler device with a nozzle actuated valve mounted in a combination fuel and nozzle passage extending through the fuel filler pipe. A drain inlet located within the combination passage captures any fuel contaminants collected during refueling. The contaminants are collected and conducted through a drain pipe connecting the drain inlet and to the vehicle exterior. The drain pipe also provides an outlet for dissipating any vacuum pressure that may buildup in the fuel filler pipe and fuel tank during refueling.
However, the inventors have recognized potential issues with such capless refueling systems. For example, absence of a drain tube to drain any contaminants that may build up in a fuel port during refueling may degrade fuel quality. Further, buildup of any partial vacuum within the fuel filler pipe and fuel tank during refueling may pose additional issues if the vacuum pressure is not adequately dissipated. On the other hand, air leakage may occur during refueling of a capless fuel port with a drain tube connecting the fuel port to the atmosphere. The air sucked into the fuel port may lead to over pressurization of an underground fuel storage tank, and may lead to service disruptions in a fueling station. Increased frequency of service disruptions at a fueling station may lead to increased downtime and higher operating costs.
The inventors herein have developed a capless fueling port to address some of issues noted above. In one example, a capless vehicle refueling port may comprise: a drain tube at a bottom of the capless port; an articulating unitary plug that flexes due to nozzle insertion to rest upon and at least partially seal the drain tube, the plug captured between an external ramped opening element and a filler pipe contiguously mounted to the external opening.
In this way, one design of a capless refueling port may be used to reduce pressure buildup in an underground fuel storage tank while allowing residual fuel vapor to be collected from the fuel port to reduce fuel emissions. For example, an articulating plug mounted in a nozzle chamber of the capless refueling port may be pressed down by a fuel nozzle during refueling to partially close an inlet of a drain tube connected to the fuel port; in the partially closed position, the articulating plug reduces air leakage from the atmosphere to an underground storage tank fluidly connected to the fuel port. The articulating plug may be further shaped and positioned to open the drain tube inlet upon removal of the fuel nozzle from the fuel port after refueling. In this way, the capless refueling port may confer several advantages. By partially closing the drain tube inlet with the articulating plug during refueling, the capless refueling port may reduce over pressurization of the underground fuel storage tank. Further, removal of the fuel nozzle after refueling allows the articulating plug to rise up and open drain tube, allowing any residual pressure (that may buildup in the fuel port during refueling) to dissipate to the atmosphere.
It should be understood that the summary above is provided to introduce in simplified form a selection of concepts that are further described in the detailed description. It is not meant to identify key or essential features of the claimed subject matter, the scope of which is defined uniquely by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to implementations that solve any disadvantages noted above or in any part of this disclosure.